Flow cytometry is an automated method for the analysis and sorting of live or fixed cells based on size and fluorescent intensity using multiple fluorescent probes that label cells based on intrinsic properties (e.g. DNA) or expression of unique protein antigens. Fluorescent activated cell sorters allow for the isolation of individual live cells (sorting) based on their antigen or protein expression profiles. Unique and rare cell types, such as stem cell or cells in specific developmental stages, can be isolated sterilely from mixtures of cells and characterized or cultured. Flow cytometry has become critical to many areas of health sciences - including cancer, immunology and regenerative medicine. The objective of this proposal is to provide state-of-the-art flow cytometry and cell sorting to a large group of NIH funded investigators. In addition, the equipment will benefit a larger group of users who perform occasional flow cytometry experiments or cell isolations. We will replace a fifteen year-old BD Vantage cell sorter instrument whose maintenance is no longer supported by the manufacturer. This speed and performance of this new iCyt flow cytometer is much improved over the Vantage sorter it is replacing, and it has additional capability to carry out sterile sorting in a biocontainment hood, a feature that greatly increases its utility to the MSU the research community. Twelve individual research projects are described that range from sorting HIV, influenza, dengue and adenovirus infected cells;to the isolation of bacteria from the human gut microbiome. Since the proposed instrument is completely contained in a laminar flow environment, it will be capable of biohazard isolation and enforcement of strict sterility.